Ultrasonic rail test device



DR mena sse M;

M y 18, 1954 H. c. DRAKE 2,678,559

ULTRASONIC RAIL TEST DEVICE Filed Dec. 29, 1951 FIG. I

FIG.2

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I, INVENTOR. R HARCOURT c. DRAKE ATTORNEY Patented May 18, 1954ULTRASONIC RAIL TEST DEVICE Harcourt C. Drake, Hempstead, N. Y.,assignor to Sperry Products, Inc., Danbury, Conn., a corporation of NewYork Application December 29, 1951, Serial No. 264,145

2 Claims.

This invention relates to the testing of rails in track by ultrasonicvibrations. Such vibrations are generated by an electro-acoustictransducer in the form of a piezo-electric quartz crystal which iselectrically energized at high frequency and which converts the electricoscillations into mechanical oscillations. The quartz crystal is mountedon a suitable support which engages the rail through a couplant, such asoil, and is moved continuously along the rails. This movement, however,creates a problem because the rail lengths are joined together by jointswhich allow considerable vertical play. As a result, there is frequentlymet the condition where the receiving end of the succeeding rail ishigher than the end of the leaving rail, causing the crystal support tostrike heavily. At best this causes rapid wear of the support, and underthe worst conditions can cause upsetting and destruction of the entiresearch unit.

It is the principal object of this invention, therefore, to providemeans for preventing excessiv wear of the support and possible upsettingof the search unit because of higher receiving ends on succeeding rails.

Further objects and advantages of this invention will become apparent inthe following detailed description thereof.

In the accompanying drawings,

Fig. 1 is a side elevation of a search unit applied to a rail, and showsthe theory underlying the invention.

Fig. 2 is a side elevation of a car and search unit, with means forremedying the condition shown in Fig. l. a

Fig. 3 is a View similar to Fig. 2, showing a modified form of theinvention.

Referring to Fig. 1, there is shown a portion of on rail of a track.Such rail consists of a plurality of rail lengths R, R joined togetherat their ends by a joint which comprises a joint bar J, bolt B extendingthrough bolt holes, and other elements not shown. There is possibilityof vertical misalignment of the rail ends, particularly under stress ofheavy loads, and a condition is frequently met where the next orsucceeding rail R has its receiving end slightly higher than the leavingend of rail R, as shown in Fig. 1.

Such a condition as described above is highly undesirable in testingrail in track by ultrasonic vibrations. In this method of testing, aquartz crystal Ill is mounted on a support I i. The support is usuallyof plastic material, and a couplant such as oil is interposed betweenthe support and the rail to facilitate transmission of vibrations intothe rail. The crystal and its support constitute a search unit which maybe suspended from a carriage l 5 by means such as a link 16 pivoted atll to the carriage and at IE to the search unit. The carriage is adaptedto ride upon the rail surface by means such as wheels [9 and issupported on a beam 2!] by means of bolts 2| fixed to carriage l5 andextending loosely through openings 22 to permit the carriage to adjustitself to the contour of the rail surface. Springs 23 normally press thecarriage toward engagement with the rail, while springs 24 interposedbetween the carriage and the search unit press the latter towardengagement with the rail. The beam 2!! may be pivoted on the front of acar 21 at 28 and can be raised and lowered by means of cable 25 andpulley 26 on the car.

In the above arrangement it will be apparent that when the condiitonshown in Fig. 1 is encountered, and the search unit is travelling in thedirection of the arrow, excessive wear and damage to the search unit canresult from striking the raised receiving end of rail R. Therefore toinsure that no such projection is encountered in the path of the movingsearch unit, I take advantage of the fact that there is a certain amountof play between the joint bars and the rails joined thereby. Such beingthe case, I provide just ahead of the carriage I5 a heavily weightedwheel 30 which will engage the receivin end of each rail just ahead ofthe search unit and depress the receiving end to a point at least flushwith the leaving end of the preceding rail, and in some cases evenslightly below such leaving end. The weight is applied to the rail insufficiently close proximity to the search unit to give said unit thefull advantage of the rail depressing effect of the weight on the rail.This will insure unopposed sliding movement of the search unit from onerail to the next.

In a modified form of the invention, shown in Fig. 3, where it ispossible to mount the search unit on the rear of the car, the entirecarriage l5 may be supported from a rearward extension 32 on the car 21,sufficiently close to the rear wheel 35 so as to take advantage of theweight of the car in depressing the receiving end of rail R.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. An ultrasonic rail testing device comprising a car adapted to travelalong the rails, the leaving end of each rail being joined to thereceiving end of the succeeding rail, an ultrasonic search unit carriedby the car and comprising an electroacoustic transducer and a supportfor said transducer adapted to slide along the rail, and means forpreventing engagement of said support with the upwardly projectingreceiving ends of the rails, said last-named means comprising a weightcarried by the car in engagement with the rail and sufiicient to depressthe rail end, and means for mounting said Weight in advance of saidsearch unit.

2. An ultrasonic rail testing device comprising a car adapted to travelalong the rails, the leaving end of each rail being joined to thereceiving end of the succeeding rail, an ultrasonic search unit carriedby the car and comprising an electroacoustic transducer and a supportfor said transducer adapted to slide along the rail, and means forpreventing engagement of said support with the upwardly projectingreceiving ends of the rails, said last-named means comprisin a weightcarried by the car in engagement with the rail and sufficient to depressthe rail end, and means for mounting said weight in advance of saidsearch unit and in sufiiciently close proximity to give the search unitthe full advantage of the rail depressing efiect of the weight on thereceiving end of the rail.

References Cited in the file Of this patent UNITED STATES PATENTS NumberName Date 2,276,011 Billstein Mar. 10, 1942 2,527,986 Carlin Oct. 31,1950

